AFLP trees versus scatterplots:: evolution and phylogeography of the polyploid complex Achillea millefolium agg. (Asteraceae)
AFLP trees versus scatterplots:: evolution and phylogeography of the polyploid complex Achillea millefolium agg. (Asteraceae)
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DOI：
10.2307/25065957
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发表时间：
2008-02-01
期刊：
影响因子：
3.4
通讯作者：
Ehrendorfer, Friedrich
中科院分区：
文献类型：
--
作者：
Guo, Yan-Ping;Saukel, Johannes;Ehrendorfer, Friedrich
千叶芹是北半球生态最多样化的多倍体复合体。由于普遍存在的杂交和多倍化，聚集体是极其多态的，并以其难以分类而闻名。AFLP分析应用于61个群体，代表了大多数已知的分类群的A。千屈菜用群体两两F-ST法和邻接法构建遗传距离树，用2D_Euklid法进行散点图分析，得到459条多态性条带。该聚合体是亚高山遗迹A的姐妹单系。latiloba-2x来自土耳其东北部和邻近的格鲁吉亚山脉。A.千屈菜在欧洲/亚洲西南部地区出现了间接分化，并扩展到了亚洲中部和东部地区。NJ树和2D_Euklid散点图都证明了这2x是遗传单系的和不同的; roseoalba-2x，与A. asplenifolia-2x，可能是杂种渐渗的产物。聚合物的多倍体（约20个分类群和细胞型）表现出各种组合的2x AFLP带，但除此之外，也有16.9%的独家带，记录新的遗传变异。而ALFP树表明大多数这些多倍体类群是多系的，AFLP 2D_Euklid散点图证明了它们的系统一致性。这种相互矛盾的证据显然是由于广泛传播的二次杂交不同的多倍体类群的同域种群之间的合并，导致在地理，而不是系统聚类的AFLP树的人口。现有的资料表明，几个平行的网状和上升的多倍体线和他们的生态地理辐射。这导致了在欧洲和高加索地区有8个4x的分类群，4个或5个6x的分类群和3个8x的分类群。其中之一，A。千屈菜亚种millefolium-6x，也出现在整个亚洲，其中两个以上的4x分类群，一个额外的6x和一个8x可以识别。最后，从与A.亚洲海峡4x，A.北极光公司进化枝起源于北美，在那里它以许多4x-和6x-生态型辐射到大多数不同的栖息地。因此，多倍体复合体A.千屈菜属，经过一系列的分化、杂交+多倍化循环，从欧洲和亚洲西南部逐步扩展到东亚，然后扩展到北美，最后以A. millefolium-6x作为杂草。
Achillea millefolium agg. is an ecologically most diverse N Hemisphere polyploid complex. Because of ubiquitous hybridization and polyploidization, the aggregate is extremely polymorphic and notorious for its difficult taxonomy. AFLP analyses were applied to 61 populations representing most of the known taxa of A. millefolium agg. Genetic distance methods of population pairwise F-ST and Neighbour Joining for tree constructions and the 2D_Euklid algorithm for scatter plots were used to evaluate the AFLP-matrix with 459, mostly polymorphic bands. The aggregate is monophyletic and sister to the subalpine relic A. latiloba-2x from NE Turkish and adjacent Georgian mountains. The seven 2x-species of A. millefolium agg. have differentiated vicariously in Europe/SW Asia and expanded into C and E Asia. Both, the NJ trees and the 2D_Euklid scatterplots demonstrate these 2x as genetically monophyletic and distinct; only A. roseoalba-2x, close to A. asplenifolia-2x, may be the product of hybrid introgression. The polyploids of the aggregate (about 20 taxa and cytotypes) exhibit various combinations of 2x AFLP bands, but in addition also 16.9% of exclusive bands, documenting new genetic variation. Whereas the ALFP trees suggest most of these polyploid taxa to be polyphyletic, the AFLP 2D_Euklid scatterplots demonstrate their phyletic coherence. This conflicting evidence apparently is due to wide-spread secondary hybrid merging between sympatric populations of different polyploid taxa, resulting in geographic instead of phyletic clustering of their populations in the AFLP trees. Available data suggest several parallel reticulating and ascending polyploid lines and their eco-geographical radiations. This has resulted in the origin of eight taxa of 4x, four or five of 6x and three of 8x in Europe and the Caucasus. One of them, A. millefolium subsp. millefolium-6x, also occurs throughout Asia, where two more 4x taxa, one additional 6x and one 8x can be recognized. Finally, from ancestors close to A. asiatica s.str.-4x, the A. borealis s.l. clade has originated in N America, where it has radiated with numerous 4x- and 6x-ecotypes into most diverse habitats. Thus, the polyploid complex A. millefolium agg., shaped by successive cycles of differentiation and hybridization + polyplodization, has expanded stepwise from Europe and SW Asia to E Asia, then to N America and finally world-wide with A. millefolium-6x as a weed.